The present disclosure relates to an optical scanning device for forming an electrostatic latent image by irradiating an image bearing member with light in an electrographic image forming apparatus, and an image forming apparatus including such an optical scanning device.
Electrographic image forming apparatuses such as color copiers, color printers, etc. include an optical scanning device. The optical scanning device irradiates a plurality of charged image bearing members with light to form an electrostatic latent image on each of the image bearing members. The optical scanning device includes a casing including an accommodation section having an open end and a covering section that covers the open end. An optical scanning system is built in the interior of the accommodation section. The covering section has an emission port for each of laser beams that each are emitted from the optical scanning system to corresponding one of the image bearing members. Each of the emission ports are covered with a transmissive member. The transmissive members are transmissive to the light (laser beams) emitted from the optical scanning system.
The transmissive members can prevent toner, dust, etc. from entering into the optical scanning device. Attachment of toner, dust, etc. to any of optical components provided in the optical scanning device may cause degradation of optical characteristics. Degradation of the optical characteristics may lead to quality degradation of an image formed on a recording medium such as paper.
In addition, attachment of toner, dust, etc. to an outer surface of one or more of the transmissive members may cause degradation of the optical characteristics. For this reason, it is necessary to periodically clean the outer surface of each of the transmissive members. An image forming apparatus of some type includes an automatic cleaning mechanism that cleans the outer surfaces of the transmissive members automatically. The automatic cleaning mechanism includes screw shafts each extending in terms of the longitudinal direction of the transmissive members. Rotation of each screw shaft moves a plurality of cleaning holders simultaneously in the same direction. Each of the cleaning holders holds a single cleaning member. The cleaning members move along their travel paths to slide on the outer surfaces of the corresponding transmissive members. Thus, the transmissive members are cleaned simultaneously.